USE/CARE OF HANDTOOLS & MEASURING TOOLS - OD1621 - LESSON 2/TASK 2
TYPES OF COMMON TAPS.
(3) Bottoming Hand Taps. Bottoming hand taps are used for threading
the bottom of a blind hole. They have a very short chamfer length of only 1
to 1 1/2 threads for this purpose. This tap is always used after the plug
tap has already been used, and for hard materials. Both the taper hand and
plug hand taps should precede the use of the bottoming hand tap.
SPECIAL PURPOSE TAPS.